The handler of a prize-winning dog who mysteriously died just days after competing at the Westminster Dog Show has said he believes the animal could have been poisoned.

Questions still surround the death of the three-year-old Samoyed named Cruz, who passed away days after taking part in the world-renowned competition in New York earlier this month.

Four days after the show - in which the dog did not place - he was in Colorado to compete in another event when he began coughing up blood and was rushed to an Animal Critical Care centre.

He was hooked up to an intravenous drip and given oxygen, but he died just hours later.

What happened to Cruz? The three-year-old prize-winning Samoyed, pictured, died days after competing in the Westminster dog show and now his handler and owners are searching for answers

A necropsy was not performed and his cause of death is unclear, but he had symptoms that strongly resembled those of dogs who had eaten rodent poison, his veterinarian told the New York Times.

His death could be explained by an undiagnosed genetic disorder, but his owners said he had no medical issues, and there were no blood disorders in his bloodline.

Now his handler and owners are looking for answers, believing he could have been the victim of poisoning at the hands of animal rights activists who might have thrown something into his cage.

Veterinarians told the Times that poison usually takes three to five days to take effect - meaning that he would have been poisoned at the New York show.

Good boy: Cruz is pictured with his handler Robert Chaffin and one of his owners Lynette Blue (centre)

Winner: His handler, Robert Chaffin, said it's possible someone might have thrown poison into the dog's cage

They added that it is unlikely he was intentionally poisoned and instead have surmised he might have eaten poison accidentally.

'Dogs are dogs,' Molly Comiskey, the veterinarian
who treated Cruz, told the Times. 'It's not anyone’s fault. They
eat stuff; they get into things; they make bad decisions.'

Handler Robert Chaffin said he rarely left the dog's side and checked their hotel room for possible poisons, as well as keeping a close eye on everything the animal ate ahead of the show.

He told the Times that he believed extreme animal
rights activists, who have protested against dog shows for being inhumane, could have been to blame.

Missed: Cruz, pictured as a puppy, had already been named Best in Breed at numerous shows this year

He said there was no evidence showing
the
dog was poisoned but agreed the animal could have swallowed something
accidentally as it would have been 'easy' for someone to throw food in
his cage.

'I've heard
horror stories about other people's dogs having their setups tampered
with, being poisoned, but I never thought it would come to me,' Chaffin said.

He recounted one man glaring at him at the competition and remarking on how Cruz's vocal chords had been removed, in a procedure called 'de-barking'.

If he was poisoned, it would not be the
first case in canine competition history. In 1895, eight dogs were
poisoned the morning before the competition, with jealousy believed to
be the cause.

People for the Ethical Treatment of
Animals sent representatives to the Westminster show to voice their
disdain and hand out leaflets, Ingrid Newkirk, the group's founder and
president, said.

Show: Poison takes three to five days to harm a dog, meaning he would have been poisoned at Westminster

Competitive: Chaffin said he had heard 'horror stories' of dogs' performances being tampered with in the past

At
this year's show, there was also a ruckus on the final night of the
competition when a protester tried to get into the exhibition ring.

Best in show: Banana Joe, an Affenpincher, took the top dog prize at the show earlier this month

But Newkirk vehemently denied the group could have had anything to do with Cruz's death.

One of the dog's owners, Lynette Blue, told the Times she had called the New York Police Department after the death and was considering which action to now take.

Although Cruz, whose full name was GCH Polar Mist Cruz’n T’Party At Zamosky, did not place at the competition, he was rising through the ranks of Samoyeds.

In 2013 alone, he had won Best of Breed titles from Kennel Club competitions in Baton Rouge, Alexandia, Ventura, San Fernando and Southeast Arkansas.

'It's devastating,' Lynette Blue, his owner, said. 'This is one of the most painful experiences of my life.'

In the poisoning case in 1895, eight dogs - including a Yorkshire terrier, a toy spaniel and a King Charles Spaniel - were poisoned.

The owner left them the night before the competition and returned to find them moaning in pain. Investigations afterwards showed strychnine 'in considerable quantity' inside the stomach of one of the dogs.

In 2010, Ralph Ullum was accused of drugging a Siberian Husky at the Wheaton Dog Show, where his girlfriend was showing a dog in the same category.

The owner of the targeted dog noticed a crushed pill near to the animal's cage and took her to the vet, who induced vomiting - and the dog survived.